Genetic diversity, structure, and patterns of differentiation in the genus Vitis

Vitis (Vitaceae) is a taxonomically complicated genus with ca. 60 taxa divided into two subgenera, Vitis and Muscadinia. We used population genetic approaches to gain insights into the genetic diversity, patterns of evolutionary differentiation and to decipher the taxonomic status of some of the controversial taxa within the genus Vitis. The distance- and model-based analyses were used to examine the phylogenetic structure within the genus Vitis using simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers. The results closely matched the current classification, but some discrepancies in the identity of taxa at the specific and subspecific levels were still evident. The East Asia and the North American Vitis exhibited strong divergence and each group showed further differentiation into several subgroups with North American subgroups roughly matching the described series. The model based cluster analysis indicated 14 clusters as optimum to explain the genetic structure within the genus Vitis with most clusters containing a moderate frequency of admixed genotypes suggesting interspecific gene flow within the subgenus Vitis. Hierarchical partitioning of molecular variation indicated that a significant amount of the total variation (~74 % and ~69 % for SSRs and AFLPs, respectively) is accounted for by intraspecific variation as compared to the levels due to genetic differentiation among species within series (~17 % and ~20 % for SSRs and AFLPs, respectively) and among series within the genus Vitis (~9 % and ~10 % for SSRs and AFLPs, respectively). Overall, Vitis possesses mild genetic structure characterized by reticulation and incomplete lineage sorting of ancestral polymorphisms.     

The pathophysiology of traumatic brain injury at a glance

Traumatic brain injury (TBI) is defined as an impact, penetration or rapid movement of the brain within the skull that results in altered mental state. TBI occurs more than any other disease, including breast cancer, AIDS, Parkinson’s disease and multiple sclerosis, and affects all age groups and both genders. In the US and Europe, the magnitude of this epidemic has drawn national attention owing to the publicity received by injured athletes and military personnel. This increased public awareness has uncovered a number of unanswered questions concerning TBI, and we are increasingly aware of the lack of treatment options for a crisis that affects millions. Although each case of TBI is unique and affected individuals display different degrees of injury, different regional patterns of injury and different recovery profiles, this review and accompanying poster aim to illustrate some of the common underlying neurochemical and metabolic responses to TBI. Recognition of these recurrent features could allow elucidation of potential therapeutic targets for early intervention.     

New sensitive light microscopical detection of colloidal gold on ultrathin sections by reflection contrast microscopy. Combination of reflection contrast and electron microscopy in post-embedding immunogold histochemistry.

One simple post-embedding method for combined light- and electron microscopy is presented. Different types of antigens in normal rat and mouse kidneys as well as in tissues from cases of experimental induced nephritis were stained after Lowicryl K4M embedding by an immunogold (silver) method. The (silver-enhanced) gold particles were visualized by light microscopy, e.g. bright-field (BFM)- and reflection contrast (RCM) microscopy, as well as by electron microscopy. The potentials of RCM visualization in this field were investigated, resulting in the successful detection of colloidal gold (15 nm) particles, or silver enhanced gold particles, on ultrathin sections. Furthermore, an increased detection sensitivity of RCM compared with BFM together with an increase in the sensitivity of the immunostaining by RCM visualization was found. The different ways to use RCM, alone or in combination with bright-field- or phase contrast microscopy for visualization of plastic sections varying in thickness, type of plastic and staining, are discussed.